1985 Chevy Nova pistons.

[SynthDesign]

It can be done. Not the best idea. But it can be done. 1 block hit a cooling pocket while being bored to .50 over on a 3A-C. The 2nd went fine and is still running.

[Petros]

if you are going to go that much oversized you should just find yourself a 4a block to rebuild. You will not regret the extra power.

the 3a block had a technical service bulletin issued for over-boring, apparently a number were delivered with the water jacket casting too close to the cylinder wall and overboring can cause a break out. the solution was to sleeve the bad cylinder. Not all have this problem, but the cost of sleeving one or more bores is more than just finding a 4a block to use as a core.